For years anyone who a) doesn't have a car, b) hates driving, c) hates being alone, or d) is burdened by the costs of owning a car and paying for gas, has observed all of the other solo drivers on the road and thought to themselves, gee, there's got to be a better way to organize this. There is just so much redundancy in the system. Some of these people should be able to share a ride, share the costs, and spare the extra cars on the road.

That's what Sunil Paul thought to himself in 1997, one day in need of a ride. "I had been reading about the idea that cell phones would have locational awareness soon," he told me, "and I thought to myself, wow, if my cell phone knows where I am, and there are all these people driving around with no one else in the car, and their cell phones know where they are, then why can't we figure out a better way for me to get home?"

But the time was not right yet -- the technology wasn't quite there, and outside of a few pockets of interest, public sentiment wasn't really there yet either. Concerns about climate change were not as deep, and many people were just okay with the car culture we had been building since at least as far back as World War II.

But in the decade-and-a-half since, a lot has changed, fueled by the growth of the Internet and the widespread adoption of smartphones. As Paul sees it, these developments don't merely enable a layer of data that makes mass ridesharing possible, but they've changed our cultural fabric, building a generalized level social trust that makes people more willing to accept a ride in the car of a stranger. Social media, says Paul, "are changing the landscape for what is possible, because they create a trust layer. We can leverage that [trust] for all kinds of new services that weren't possible before." (By social media, Paul says, he means more than just Facebook, but any site online, like Wikipedia and Yelp, that allows people to work with and communicate with people they don't know.) The convergence of these three changes -- the proliferation of smartphones, the development of social media, and the increased concern about car culture for a host of environmental and social reasons -- means that we can start building transportation systems whose center of gravity is information technology, accessed through your cell phone, not the personal automobile.

Now, building on that possibility, Paul's company has released its ridesharing app, SideCar, available on iOS and Android phones. With SideCar, vetted drivers (who have passed through background checks and other safety measures) and passengers can match up for a ride, and though the ride is technically free, passengers are given the opportunity to donate a "community average" that goes to the driver to help defray the costs of car ownership (and incentivize ride offering, a constant hurdle for services that try to pair up passengers and drivers). All of the transactions are handled without cash through the app. For the time being, the service is only available in the Bay Area, but SideCar hopes to roll it out in other cities later this year. Since its initial beta release in late winter, more than 10,000 rides have been shared.

Paul says one thing they've been surprised about is that for many people the service has become more than just a convenient way to get around; it's a social experience too. He and his team have heard stories about people being matched up for rides and then going to concerts (and even a golf tournament!) together. "We live in a pretty lonely society, and by that I don't mean the US or San Francisco. I mean the world ever since industrialization," Paul says. And the automobile, for all the freedoms it's afforded, have contributed to that. "If you look at how we spend our time, the loneliest time we have is when we are in our cars," Paul notes. "I've driven people around and it's just interesting. There are all kinds of interesting people in the world."

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Rebecca J. Rosen is a senior editor at The Atlantic, where she oversees the Family and Education sections.